1. Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method for detecting a received signal in a multiple input multiple output (MIMO) transceiving system and a method for supporting the same.
2. Related Art
Recently, various wireless communication technologies are under development with advancement of information communication technologies. In addition, in the recent wireless communication environment, high-rate data transmission is required, but available wireless resources have a limitation. Therefore, an interest in a method for increasing throughput of wireless communication has been increased. This increases an interest in a multiple input multiple output (MIMO) transmission mechanism in a wireless communication system.
Indices of determining performance of a wireless communication system may be a data throughput and a link range. The MIMO transmission mechanism may improve a data throughput and a link range of wireless communication without an increase in a bandwidth of a usable frequency and a transmission power for data transmission. This MIMO transmission has been supported in IEEE 802.11n, 3GPP long term evolution (LTE), WiMAX, HSPA+, or the like. The tendency to apply the MIMO transmission to a digital video broadcasting (DVB) system has currently appeared.
Unlike the existing transmission mechanisms for performing wireless communication using a single antenna, a wireless communication system supporting the MIMO transmission mechanism uses a plurality of antennas to simultaneously transmit the same data several times or transmits another data through another antenna, thereby improving the reliability of transmission and the throughput of the entire wireless communication system.
In order to approximate theoretical channel capacity using a system with a channel code concatenated with a vertical bell labs layered space-time architecture (V-BLAST) system suggested as a practical MIMO system, a need exists for a process of creating soft decision information as an input of a channel decoder from the V-BLAST system. The soft decision information as the input of the channel decoder corresponds to a log-likelihood ratio (LLR) for each transmitting bit mapped to modulated constellation. When performing the soft decision according to a maximum likelihood algorithm, calculation complexity is increased with the increase in the number of antennas configuring the MIMO transceiving system, which leads to many limitations to implement the maximum likelihood algorithm using a substantial hardware. On the other hand, other algorithms proposed so as to lower the calculation complexity have considerable deterioration in performance, as compared with the maximum likelihood algorithm. Therefore, a need exists for an algorithm having little deterioration in performance while lowering the calculation complexity, as compared with the maximum likelihood algorithm.